Method of treating virus-induced cancer

ABSTRACT

The present invention relates to methods of treating virus-induced cancer with the polypeptides that are capable of killing cells. The polypeptide comprises a targeting agent covalently attached to a channel-forming moiety. In a preferred embodiment, the channel-forming moiety comprises a colicin and the targeting agent is a reconstructed antibody mimetic derived from monoclonal antibody variants against Epstein-Barr virus gp350/220

This patent application is a divisional of patent application Ser. No.11/297,464 filed Dec. 9, 2005, which claims priority to Chinese PatentApplication 200410081446.8 filed Dec. 10, 2004, which patent documentsare incorporated herein by specific reference in their entirety.

BACKGROUND OF INVENTION Field of the Invention

As a result of industrial globalization, viral infection by, forexample, viral hepatitis, influenza, pneumonia, encephalitis,virus-induced carcinoma and acquired immune deficiency syndrome (AIDS)is becoming an epidemic phenomenon. Virus-induced cancer is becoming apredominant menace to human life. Traditional approaches to thedevelopment of antiviral drugs usually attempt to disturb the metabolismof viral genes, interfere with the activity of viral enzymes, or useimmunology approaches, such as antibodies and immune factors, to provideviral vaccines. Unfortunately, these drugs often lose their efficaciesquickly because a virus can develop resistance through mutation.

Resistance to antiviral therapy has become a major issue in themanagement of patients with chronic viral infections. Perhaps the bestknow example is human immunodeficiency virus (HIV), but herpes simplexvirus, hepatitis B and C virus, and Epstein-Barr virus exhibit similarcapabilities. Accordingly, a need exists for compounds and methods oftreating viral infections and drug resistant virus.

According to the most recent data available from the American CancerSociety, cancer is the second leading cause of death in the UnitedStates trailing only heart disease. Nearly one quarter of all deaths inthe United States are caused by cancer.

Many types of chemotherapeutic agents have been shown to be effectiveagainst cancers and tumor cells, but not all types of cancers and tumorsrespond to these agents. Unfortunately, many of these agents alsodestroy normal cells.

Despite advances in the field of cancer treatment, the leading therapiesto date are surgery, radiation and chemotherapy. Chemotherapeuticapproaches work best on cancers that are metastasized or ones that areparticularly aggressive, i.e., ones whose cells are rapidly dividing.Ideally cytotoxic agents would have specificity for cancer and tumorcells while not affecting normal cells.

The development of materials that would specifically target cancer cellsis extremely desirable. In addition, materials that are cytotoxic tocancer cells while exerting mild effects on normal cells would alsodesirable.

Accordingly, new and effective cancer treatments are needed to treatsubjects that have, or will develop, cancer.

SUMMARY OF THE INVENTION

The instant invention is based on the discovery that a bifunctionalmolecule comprising a targeting agent and a channel-forming moiety canselectively kill cells, e.g., cancer cells. The invention provides anovel class of preferred compounds that kill cells. Accordingly, in oneaspect, the instant invention provides a molecule comprising a targetingagent attached to a channel-forming moiety. In one embodiment, themolecule is a polypeptide.

In certain embodiments, the channel-forming moiety is a channel-formingpeptide, a channel-forming domain, or fragment thereof. For example, thechannel-forming peptide can be α-hemolysin, delta toxin, diphtheriatoxin, anthrax toxin, and E1 family colicin. In particular embodimentsthe colicin is E1, Ia, Ib, A, K or N. In one particular embodiment, thecolicin is colicin Ia.

In a related embodiment, the channel-forming fragment is achannel-forming colicin comprising amino acid residues from about 1 toabout amino acid 626 of colicin Ia (SEQ ID NO:1) having the nucleic acidsequence of SEQ ID NO:2. In a specific embodiment, the channel-formingdomain comprises amino acid residues 451-626 (SEQ ID NO:3) having thenucleic acid sequence of SEQ ID NO:4.

In specific embodiments, the targeting agent is selected from the groupconsisting of a ligand, an antibody, an antibody fragment, areconstituted antibody mimetic, and a phage segment.

In one embodiment the targeting agent is C-terminal to thechannel-forming moiety. In an alternative embodiment, the targetingagent is N-terminal to the channel-forming moiety.

In another embodiment, the targeting agent is an antibody or fragmentthereof, or a reconstituted antibody mimetic.

In a related embodiment, the antibody, a fragment thereof, or areconstituted antibody mimetic is a specific for a polypeptide expressedby a cell, e.g., a cancer cell. In a related embodiment, the antibody isan engineered antibody variant or a reconstituted antibody mimetic.

In one aspect, the invention provides a polypeptide comprising anantibody and a channel-forming colicin, or a channel-forming fragmentthereof, of colicin. In a related embodiment, the colicin comprisesresidues 1-626 of colicin Ia. In a specific embodiment, thechannel-forming domain comprises residues 451-626 of colicin Ia.

In one aspect, the invention provides a polypeptide comprising theEpstein-Barr virus gp350/220 envelope glycoprotein engineered antibodyvariant, or a reconstituted antibody mimetic, and a channel-formingdomain of colicin. In a specific embodiment, the channel-forming domainof colicin comprises residues from about residue 1 to about residue 626of colicin Ia. Ia specific embodiment, the channel-forming domaincomprises amino acid residues 451-626.

In a related embodiment, the polypeptides of the invention may have oneor more non-natural amino acid residues, e.g., amino acid analogs, ormimetics.

In a specific embodiment, the non-natural amino acid residues areD-isomers of natural amino acid residues.

In another aspect, the invention provides a nucleic acid molecule thatencodes a polypeptides of the invention.

In a related embodiment, the invention provides a vector, e.g., anexpression vector, comprising a nucleic acid molecule that encodes apolypeptide of the invention.

In a related embodiment, the invention provides a host cell comprising avector of the invention. In a specific embodiment, the host cell is abacterial cell, e.g., E. coli, or a yeast or mammalian host cell.

In another aspect, the invention further provides methods of producingthe polypeptide of the invention. The methods comprise the steps ofculturing the host cells of the invention such that the polypeptides areproduced. In a further embodiment, the methods of the invention mayinvolve purifying said polypeptide.

In another aspect, the invention provides a method of producing amolecule of the invention wherein the targeting agent and thechannel-forming moiety are produced separately and covalently linkedafter production. In a related embodiment, the channel-forming moietyand/or the targeting agent are produced recombinantly.

In another aspect, the invention provides methods of treating a subjecthaving cancer, comprising administering to the subject an effectiveamount of a polypeptide comprising an targeting agent and achannel-forming moiety thereby treating the subject.

In a related embodiment, the targeting agent is selected from the groupconsisting of an antibody, a fragment thereof, an engineering antibodyvariant, and a reconstituted antibody mimetic. In a specific embodiment,the reconstituted antibody mimetic or variants was a complementaritydetermining regions pair (V_(H)CDR1 and V_(L)CDR3) selected from theantibody fragment against EBV gp350/220 envelope glycoprotein.

In one embodiment, the channel-forming moiety is selected from the groupconsisting of α-hemolysin, delta toxin, diphtheria toxin, anthrax toxin,and E1 family colicin, or a fragment thereof. In specific embodimentsthe colicin, or the fragment of colicin, is selected from the groupconsisting of E1, Ia, Ib, A, K or N. In one particular embodiment, thecolicin is colicin Ia. In further particular embodiments, the fragmentof colicin Ia comprises amino acid residues 1-626 or 451-626.

In another aspect, the invention provides a method of treating a subjecthaving a viral associated cancer comprising administering to the subjectan effective amount of a polypeptide comprising an targeting agent and achannel-forming moiety thereby treating said subject.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically depicts the structure of a recombinant plasmid thatcontains a complementarity determining region pair as a targeting domainwhich is selected from a FIB-168 monoclonal antibody fragment againstEpstein-Barr virus gp350/220 envelope antigen and linked to aVHCDR1/VHCDR2 linker of that fragment

FIG. 2 schematically depicts the structure of a recombinant plasmid thatcontains a targeting domain derived from bacteriophage M13.

FIG. 3A-B depict images of EBV-infected Burkitt's malignant lymphomacells after 72 hours of treatment with Ph-CNCV. FIG. 3A is a CCD imageof cells treated with stock solution of pheromonicin as a control. FIG.3B is a CCD image of cells treated with 50 μg/ml of Ph-CNCV. Cells arestained with 50 nM acridinorange/600nM propidium iodide. Cellularswelling, mitochondria degeneration and cell rupture were detected alongwith the Ph-CNCV.

FIG. 4A-B depict images of human EBV-infected Burkitt's malignantlymphoma cells after 72 hours of treatment with Ph-EBV. FIG. 4A is a CCDimage of cells treated with stock solution of pheromonicin as a control.FIG. 4B is a CCD image of cells treated with 50 μg/ml of Ph-EBV. Cellsare stained with 50 nM acridinorange/600 nM propidium iodide. Cellularswelling, mitochondria degeneration and cell rupture were detected alongwith the Ph-EBV.

FIG. 5A-B depict images of human EBV-uninfected Burkitt's malignantlymphoma cells after 72 hours of treatment with Ph-EBV. FIG. 5A is a CCDimage of cells treated with stock solution of pheromonicin as a control.FIG. 5B is a CCD image of cells treated with 50 μg/ml of Ph-EBV. Cellsare stained with 50 nM acridinorange/600 nM propidium iodide. Ph-EBV hasno effects on EBV-uninfected lymphoma cells.

FIG. 6A-B depict images of human EBV-infected AIDS related body cavitybased lymphoma cells after 72 hours of treatment with Ph-EBV. FIG. 6A isa CCD image of cells treated with stock solution of pheromonicin as acontrol. FIG. 6B is a CCD image of cells treated with 50 μg/ml ofPh-EBV. Cells are stained with 50 nM acridinorange/600 nM propidiumiodide. Cellular swelling, mitochondria degeneration and cell rupturewere detected along with the Ph-EBV.

FIG. 7A-B depict images of SMMC-7721 human hepatocellular cancer cellsafter 72 hours of treatment with Ph-EBV. FIG. 7A is a CCD image of cellstreated with stock solution of pheromonicin as a control. FIG. 7B is aCCD image of cells treated with 50 μg/nil of Ph-EBV. Cells are stainedwith 50 nM acridinorange/600 nM propidium iodide. Ph-EBV has no effectson hepatoma cells.

FIG. 8A-B depict images of ATCC 3T3 mouse fibroblast cells after 72hours of treatment with Ph-EBV. FIG. 8A is a CCD image of cells treatedwith stock solution of pheromonicin as a control. FIG. 8B is a CCD imageof cells treated with 50 μg/ml of Ph-EBV. Cells are stained with 50 nMacridinorange/600 nM propidium iodide. Ph-EBV has no effects onfibroblast cells.

FIG. 9A-B depict images of ECV-304 human umbilical cord vein endotheliumcells after 72 hours of treatment with Ph-EBV. FIG. 11A is a CCD imageof cells treated with stock solution of pheromonicin as a control. FIG.9B is a CCD image of cells treated with 50 μg/ml of Ph-EBV. Cells arestained with 50 nM acridinorange/600 nM propidium iodide. Ph-EBV has noeffects on endothelium cells.

FIG. 10A-F shows the killing effects of Ph-EBV against xenograftinoculated with tumor cells in immunodeficiency mice as solid tumormodels. FIG. 10A depicts exposed xenografts after 16-day intraperitonealPh-EBV stock solution treatment (0.5 ml/mouse/day). FIG. 10B depictsexposed xenografts after 16-day intraperitoneal Ph-EBV treatment ((350μg/mouse/day)). FIG. 10C depicts a 400× microscope image ofEBV-uninfected xenograft in stock solution-treated mouse. FIG. 10Ddepicts a 400× microscope image of EBV-infected xenograft in stocksolution-treated mouse. FIG. 10E depicts a 400× microscope image ofEBV-uninfected xenograft in Ph-EBV-treated mouse. FIG. 10F depicts a400× microscope image of EBV-infected xenograft in Ph-EBV-treated mouse.

FIG. 11A-K shows the killing effects of Ph-EBV against solid tumors.FIG. 11A depicts an exposed Burkitt Lymphoma xenograft after 20-dayintraperitoneal Ph-EBV stock solution treatment (0.5 ml/mouse/day). FIG.11B depicts a 100× microscope image of the xenograft. FIG. 11 C depictsexposed Burkitt Lymphoma xenograft after 20-day intraperitoneal Ph-EBVtreatment (350 μg/mouse/day). FIG. 11D depicts a 100× microscope imageof the xenograft. FIG. 11E depicts exposed AIDS related body cavitybased lymphoma xenograft after 20-day intraperitoneal Ph-EBV stocksolution treatment (0.5 ml/mouse/day). FIG. 11F depicts a 100×microscope image of the xenograft. FIG. 11G depicts an exposed AIDSrelated body cavity based lymphoma xenograft after 20-dayintraperitoneal Ph-EBV treatment (350 μg/mouse/day). FIG. 11H depicts a100× microscope image of the xenograft. FIG. 11I depicts exposednasopharyngeal cancer xenograft after 20-day intraperitoneal Ph-EBVstock solution treatment (0.5 ml/mouse/day). FIG. 11J depicts a 100×microscope image of the xenograft. FIG. 11K depicts exposednasopharyngeal cancer after 20-day intraperitoneal Ph-EBV treatment (350μg/mouse/day). FIG. 11L depicts 100× microscope image of the xenograft.Inset: enlarged view of rectangle area where nasopharyngeal cells wereundergoing coagulative necrosis (arrows).

FIGS. 12A-G show the targeting distribution of circulating FITC-labeledPh-EBV, Ph-SA or HB-168 IgG molecules in immunodeficiency mice withEBV-infected and EBV-uninfected Burkitt Lymphoma xenografts. Xenograftsof a BALB/C nude mouse were inoculated either with EBV-infected (rightside) or with EBV-uninfected (left side) Burkitt Lymphoma cells atrespective forelimb armpits of the same mouse. FIG. 12A depicts theFITC-labeled Ph-EBV in vivo image at 1 hour after intraperitoneal Ph-EBVgiven. FIG. 12B depicts the image at 2 hours after intraperitonealPh-EBV given. FIG. 12C depicts the image at 3 hours afterintraperitoneal Ph-EBV given. FIG. 12D depicts the image at 6 hoursafter intraperitoneal Ph-EBV given. FIG. 12E depicts the image at 3hours after intraperitoneal HB-168 given. FIG. 12F depicts the image at6 hours after intraperitoneal HB-168 given. FIG. 12G depicts the imageat 6 hours after intraperitoneal Ph-SA given.

FIG. 13A-D shows the presence or absence damage in visceral organs ofregular mouse after 30-day intraperitoneal Ph-EBV treatment (700μg/mouse/day). FIG. 13A depicts a 100× microscope image of liver. FIG.13B depicts a 100× microscope image of intestine. FIG. 13C depicts a100× microscope image of kidney. FIG. 13D depicts 100× microscope imageof spleen.

DETAILED DESCRIPTION

Before further description of the invention, certain terms employed inthe specification, examples and appended claims are, for convenience,explained here.

The term “targeting agent” is intended to include molecules, e.g., smallmolecules, peptides, and polypeptides, that specifically recognize giventypes of cells. These agents can bind to a polypeptide or carbohydrateexpressed by a cell, e.g., on the surface of a cancer cell. Nonlimitingexamples of the targeting agents of the invention include antibodies,engineered antibody variants, reconstituted antibody mimetics, fragmentsof antibodies, single domain antibodies, phage segments or smallmolecules. These targeting agents can recognize a polypeptide expressedby a cancerous cell or a viral peptide expressed by a cancerous cell.Exemplary, non-limiting, cell produced polypeptides include Her2,estrogen receptor, progesterone receptor, STEAP, carcinoembryonicantigen, prostate carcinoma tumor antigen and T-antigen. In furtherembodiments, the targeting agent may be a ligand that binds to areceptor expressed by a cancer cell, e.g., estrogen receptor.

The term “channel-forming moiety” is intended to include transmembranepolypeptides that are capable of inserting into a lipid bilayer therebycreating a gating passageway, from inside of the cell compartment tooutside of the cell compartment. In preferred embodiments, the gatingpassageway is not specific in term of what is permitted to pass throughthe channel. Exemplary channel-forming moieties are polypeptides thatnaturally form channels in lipid bilayers, i.e., α-hemolysin, deltatoxin, diphtheria toxin, anthrax toxin, and E1 family colicin,Channel-forming moieties can also be fragments of naturally occurringpolypeptides that retain the ability to insert into a lipid bilayer andform a channel. One of skill in the art would be able to isolate manyfragments of naturally occurring polypeptides that have the ability toform a channel. Those channel-forming fragments are intended to be usedin the methods and compositions of the instant invention.

The term “antibody” as used herein refers to immunoglobulin moleculesand immunologically active portions of immunoglobulin molecules, i.e.,molecules that contain antigen binding sites which specifically bind(immunoreacts with) an antigen. Nonlimiting examples of immunologicallyactive portions of immunoglobulin molecules include F(ab) and F(ab′)₂fragments which can be generated by treating the antibody with anenzyme, such as pepsin.

The invention provides polyclonal and monoclonal antibodies. The term“monoclonal antibody” or “monoclonal antibody composition”, as usedherein, refers to a population of antibody molecules that contain onlyone species of an antigen binding site capable of immunoreacting with aparticular epitope. A monoclonal antibody composition thus typicallydisplays a single binding affinity for a particular protein with whichit immunoreacts.

The term “reconstituted antibody mimetic” refers to a targeting agentcomprising one or more antibody complementarity determining regions(CDRs) covalently linked to, for example, a polypeptide linker. Forexample, V_(H)CDR1, V_(H)CDR2, V_(H)CDR3, V_(L)CDR1, V_(L)CDR2, orV_(L)CDR3 regions from light or heavy chains of an antibody fragment maybe covalently attached to confer binding affinity, i.e., sufficientbinding ability to allow the molecules of the invention to target a celland allow for insertion of the channel-forming domain into the lipidbilayer. The CDRs may be linked together directly, by using randompeptides, or by using the natural linking peptides present in antibodyheavy or light chains. The CDR regions are generally from an antibodythat specifically recognizes an epitope presented by a target cell. In aspecific embodiment, the reconstituted antibody mimetic or variants area complementarity determining region pair (V_(H)CDR1 and V_(L)CDR3)selected from the antibody fragment linked by naturalV_(H)CDR1/V_(H)CDR2 linker.

The terms “protein” and “polypeptide” are used interchangeably herein.The term “peptide” is used herein to refer to a chain of two or moreamino acids or amino acid analogs (including non-naturally occurringamino acids and amino acid analogues), with adjacent amino acids joinedby peptide (—NHCO—) bonds. Thus, peptides in accordance with theinvention include oligopeptides, polypeptides, proteins, andpeptidomimetics.

The term “fragment” refers to any portion of a natural, recombinant orsynthetic polypeptide. A fragment can be made synthetically,enzymatically, or recombinantly.

The term “pharmaceutical composition” includes preparations suitable foradministration to mammals, e.g., humans. When the compounds of thepresent invention are administered as pharmaceuticals to mammals, e.g.,humans, they can be given as is or as a pharmaceutical compositioncontaining, for example, 0.1 to 99.5% of active ingredient incombination with a pharmaceutical acceptable carrier. Pharmaceuticalcompositions of the current invention may further contain, for example abiocide, antimicrobial, or antibiotic.

As used herein, the term “cell proliferative disorder” is intended toinclude diseases or disorders characterized by abnormal cell growth,e.g., cancer.

As used herein, the term “abnormal cell growth” is intended to includecell growth which is undesirable or inappropriate. Abnormal cell growthalso includes proliferation which is undesirable or inappropriate (e.g.,unregulated cell proliferation or undesirably rapid cell proliferation).Abnormal cell growth can be benign and result in benign masses oftissues or cells, or benign tumors. Abnormal cell growth can also bemalignant and result in malignancies, malignant masses of tissues orcells, or malignant tumors. Many art-recognized conditions and disordersare associated with malignancies, malignant masses, and malignant tumorsincluding cancer and carcinoma.

As used herein, the term “tumor” is intended to encompass both in vitroand in vivo tumors that form in the body. Tumors may be associated withbenign abnormal cell growth (e.g., benign tumors) or malignant cellgrowth (e.g., malignant tumors).

“Cancer” includes a malignant neoplasm characterized by deregulated oruncontrolled cell growth. The term “cancer” includes primary malignanttumors (e.g., those whose cells have not migrated to sites in thesubject's body other than the site of the original tumor) and secondarymalignant tumors (e.g., those arising from metastasis, the migration oftumor cells to secondary sites that are different from the site pf theoriginal tumor). Cancer may develop in, for example, the followingtissues: larynx, prostate, stomach, skin, oral cavity, pharynx,esophagus, liver, lung, head, neck, bronchus, pancreas, small intestine,colon, rectum, breast, bladder, uterus, brain, lymph system, blood,ovaries, kidneys, or soft tissue.

The histological features of cancer are summarized by the term“Anaplasia”. Malignant neoplasms often contain numerous mitotic cells.These cells are typically abnormal. Such mitotic aberrations account forsome of the karyotypic abnormalities found in most cancers. Bizarremultinucleated cells are also seen in some cancers, especially thosewhich are highly anaplastic. “Dysplasia” refers to a pre-malignant statein which a tissue demonstrates histologic and cytologic featuresintermediate between normal and anaplastic. Dysplasia is oftenreversible.

“Anaplasia” refers to the histological features of cancer. Thesefeatures include derangement of the normal tissue architecture, thecrowding of cells, lack of cellular orientation termed dyspolarity,cellular heterogeneity in size and shape termed “pleomorphism.” Thecytologic features of anaplasia include an increased nuclear-cytoplasmicratio (the nuclear-cytoplasmic ratio can be over 50% for malignantcells), nuclear pleomorphism, clumping of the nuclear chromatin alongthe nuclear membrane, increased staining of the nuclear chromatin,simplified endoplasmic reticulum, increased free ribosomes, pleomorphismof mitochondria, decrease in size and number of organelles, enlarged andincreased numbers of nucleoli, and sometimes the presence ofintermediate filaments.

“Neoplasis” or “neoplastic transformation” is the pathologic processthat results in the formation and growth of a neoplasm, tissue mass, ortumor. Such process includes uncontrolled cell growth, including eitherbenign or malignant tumors. Neoplasms include abnormal masses of tissue,the growth of which exceeds and is uncoordinated with that of the normaltissues and persists in the same excessive manner after cessation of thestimuli which evoked the change. Neoplasms may show a partial orcomplete lack of structural organization and functional coordinationwith the normal tissue, and usually form a distinct mass of tissue.

Neoplasms tend to morphologically and functionally resemble the tissuefrom which they originated. For example, neoplasms arising within theislet tissue of the pancreas resemble the islet tissue, containsecretory granules, and secrete insulin. Clinical features of a neoplasmmay result from the function of the tissue from which it originated.

By assessing the histologic and other features of a neoplasm, it can bedetermined whether the neoplasm is benign or malignant. Invasion andmetastasis (the spread of the neoplasm to distant tissue) are definitiveattributes of malignancy. Despite the fact that benign neoplasms mayattain enormous size, they remain discrete and distinct from theadjacent non-neoplastic tissue. Benign tumors are generally wellcircumscribed and round, have a capsule, and have a grey or white color,and a uniform texture. By contrast, malignant tumor generally havefingerlike projections, irregular margins, are not circumscribed, andhave a variable color and texture. Benign tumors grow by pushing onadjacent tissue as they grow. As the benign tumor enlarges it compresesadjacent tissue, sometimes causing atrophy. The junction between abenign tumor and surrounding tissue may be converted to a fibrousconnective tissue capsule allowing for easy surgical remove of benigntumors. By contrast, malignant tumors are locally invasive and grow intothe adjacent tissues usually giving rise to irregular margins that arenot encapsulated making it necessary to remove a wide margin of normaltissue for the surgical removal of malignant tumors. Benign neoplasmstends to grow more slowly than malignant tumors. Benign neoplasms alsotend to be less autonomous than malignant tumors. Benign neoplasms tendto closely histologically resemble the tissue from which theyoriginated. More highly differentiated cancers, cancers that resemblethe tissue from which they originated, tend to have a better prognosisthan poorly differentiated cancers. Malignant tumors are more likelythan benign tumors to have an aberrant function (i.e. the secretion ofabnormal or excessive quantities of hormones).

The term “subject” includes organisms which can suffer from cancer. Theterm subject includes mammals, e.g., horses, monkeys, bears, dogs, cats,mice, rabbits, cattle, squirrels. Rats, and, preferably, humans.

Molecules of the Invention

The present invention provides molecules, e.g., fusion molecules,comprising a targeting agent and a channel-forming moiety. The targetingagent can be a small molecule, peptide, e.g., an antibody, orpeptidomimetic. Accordingly, the polypeptides of the invention arethreefold: a polypeptides comprising a targeting agent, a polypeptidecomprising a channel-forming moiety, and a polypeptide comprising atargeting agent and a channel-forming moiety.

Targeting agents of the invention serve to bring a fusion molecule inclose proximity to the surface of a cell, e.g., a cancer cell.

One class of targeting agents of the invention are small molecules thatbind to receptors expressed on the surface of an cell.

A second class of targeting agents are peptides, or polypeptides, thatspecifically bind to proteins on a cell surface, e.g., an antibody. Inone embodiment, the peptides are molecules that bind to a cell surfacereceptor. In another embodiment, the peptides are molecules that bind toa cell surface antigen, e.g., antibodies, reconstituted antibodies,ScFvs, or fragments thereof.

A preferred polypeptide that is capable of acting as a targeting agentis an antibody or a reconstituted antibody mimetic. Antibody fragments,e.g., Fab fragments or reconstituted antibody mimetics, preferablyretain the ability to specifically recognize a target cell. Areconstituted antibody mimetic derived from a complementaritydetermining regions pair (V_(H)CDR1 and V_(L)CDR3) selected from theantibody fragment linked by natural V_(H)CDR1/V_(H)CDR2 linker iscapable of acting as such a targeting agent.

Reconstituted antibody mimetic molecules that specifically recognize anantigen on the cell surface of a cell, e.g., a viral antigen or cancercell marker, can be used as the targeting agent. Specifically,reconstituted antibody mimetic molecules that recognize viral peptides,e.g., herpes virus particles or channel-forming domains thereof, can beused as a channel-forming polypeptide of the invention. Exemplary,non-limiting mimetic molecules that are contemplated for use in themethods and compositions of the invention are the variants ofcomplementarity determining regions pairs selected from the antibodyfragment against Epstein-Barr virus gp350/220 envelope glycoprotein.

Another preferred class of targeting agents are antibodies againsttarget cell surface polypeptides that are differentially expressed incancer cells. For example, a number of polypeptides are known that areexpressed at higher levels in cancer cells than in normal non-cancerouscells. Exemplary polypeptides that are differentially expressed in oneor more cancerous tissues are Her2, estrogen receptor, progesteronereceptor, STEAP, carcinoembryonic antigen, prostate carcinoma tumorantigen and T-antigen.

Nucleic Acid Molecules of the Invention

Another aspect of the invention pertains to vectors, preferablyexpression vectors, containing a nucleic acid molecule encoding apolypeptide of the invention (or a portion thereof). As used herein, theterm “vector” refers to a nucleic acid molecule capable of transportinganother nucleic acid molecule to which it has been linked. One type ofvector is a “plasmid”, which refers to a circular double stranded DNAloop into which additional DNA segments can be ligated. Another type ofvector is a viral vector, wherein additional DNA segments can be ligatedinto the viral genome. Certain vectors are capable of autonomousreplication in a host cell into which they are introduced (e.g.,bacterial vectors having a bacterial origin of replication and episomalmammalian vectors). Other vectors (e.g., non-episomal mammalian vectors)are integrated into the genome of a host cell upon introduction into thehost cell, and thereby are replicated along with the host genome.Moreover, certain vectors are capable of directing the expression ofgenes to which they are operatively linked. Such vectors are referred toherein as “expression vectors”. In general, expression vectors are oftenin the form of plasmids. In the present specification, “plasmid” and“vector” can be used interchangeably as the plasmid is the most commonlyused form of vector. However, the invention is intended to include suchother forms of expression vectors, such as viral vectors (e.g.,replication defective retroviruses, adenoviruses and adeno-associatedviruses), which serve equivalent functions.

The recombinant expression vectors of the invention comprise a nucleicacid molecule of the invention in a form suitable for expression of thenucleic acid molecule in a host cell, which means that the recombinantexpression vectors include one or more regulatory sequences, selected onthe basis of the host cell to be used for expression, which areoperatively linked to the nucleic acid sequence to be expressed. Withina recombinant expression vector, “operably linked” is intended to meanthat the nucleotide sequence of interest is linked to the regulatorysequence(s) in a manner which allows for expression of the nucleotidesequence (e.g., in an in vitro transcription/translation system or in ahost cell when the vector is introduced into the host cell). The term“regulatory sequence” is intended to include promoters, enhancers andother expression control elements (e.g., polyadenylation signals). Suchregulatory sequences are described, for example, in Goeddel; GeneExpression Technology: Methods in Enzymology 185, Acedemic Press, SanDiego, Calif. (1990). Regulatory sequences include those which directconstitutive expression of a nucleotide sequence in many types of hostcells and those which direct expression of the nucleotide sequence onlyin certain host cells (e.g., tissue-specific regulatory sequences). Itwill be appreciated by those skilled in the art that the design of theexpression vector can depend on such factors as the choice of the hostcell to be transformed, the level of expression of protein desired, andthe like. The expression vectors of the invention can be introduced intohost cells to produce proteins or peptides, including fusion proteins orpeptides, encoded by nucleic acids as described herein (e.g.,polypeptides comprising a targeting domain and a channel-formingpolypeptide).

The recombinant expression vectors of the invention can be designed forexpression of the polypeptides of the invention in prokaryotic oreukaryotic cells. For example, the polypeptides can be expressed inbacterial cells such as E. coli, insect cells (using baculovirusexpression vector) yeast cells or mammalian cells. Suitable host cellsare discussed further in Goeddel; Gene Expression Technology: Methods inEnzymology 185, Acedemic Press, San Diego, Calif. (1990). Alternatively,the recombinant expression vector can be transcribed and translated invitro, for example using T7 promoter regulatory sequences and T7polymerase.

Expression of proteins in prokaryotes is most often carried out in E.coli with vectors containing constitutive or inducible promotersdirecting the expression of either fusion or non-fusion proteins. Fusionvectors add a number of amino acids to a protein encoded therein,usually to the amino terminus of the recombinant protein. Such fusionvectors typically serve three purposes: 1) to increase expression ofrecombinant protein; 2) to increase the solubility of the recombinantprotein; and 3) to aid in the purification of the recombinant protein byacting as a ligand in affinity purification. Often, in fusion expressionvectors, a proteolytic cleavage site is introduced at the junction ofthe fusion moiety and the recombinant protein to enable separation ofthe recombinant protein from the fusion moiety subsequent topurification of the fusion protein. Such enzymes, and their cognaterecognition sequences, including Factor Xa, thrombin and enterokinase.Typical fusion expression vectors include pGEX (Pharmacia Biotech Inc;Smith, D. B. and Johnson, K. S. (1988) Gene 67:31-40), pMAL (New EnglandBiolabs, Beverly, Mass.) and pRIT5 (Pharmacia, Piscataway, N.J.) whichfuse glutathione S-transferase (GST), maltose E binding protein, orprotein A, respectively, to the target recombinant protein.

Examples of suitable inducible non-fusion E.coli expression vectorsinclude pTrc(Amann et al., (1988) Gene 69:301-315) and pET 11d (Studieret al., Gene Expression Technology: Methods in Enzymology 185, AcedemicPress, San Diego, Calif. (1990) 69-89). Target gene expression from thepTrc vector relies on host RNA polymerase transcription from a hybridtrp-lac fusion pomoter. Target gene expression from the pET 11d vectorrelies on transcription from a T7 gn10-lac fusion promoter mediated by acoexpressed viral RNA polymerase (T7gn1). This viral polymerase issupplied by host strains BL21 (DE3) from a resident prophage harboring aT7 gn1 gene under the transcriptional control of the lacUV 5 promoter.

One strategy to maximize recombinant protein expression in E. coli is toexpress the protein in a host bacteria with an impaired capacity toproteolytically cleave the recombinant protein (Gottesman, S., GeneExpression Technology: Methods in Enzymology 185, Acedemic Press, SanDiego, Calif. (1990) 119-128). Another strategy is to alter the nucleicacid sequences of the nucleic acid to be inserted into an expressionvector so that the individual codons for each amino acid are thosepreferentially utilized in E.coli (Wada et al., (1992) Nucleic AcidsRes. 20:2111-2118). Such alteration of nucleic acid sequences of theinvention can be carried out by standard DNA synthesis techniques.

In another embodiment, the expression vector is a yeast expressionvector. Examples of vectors for expression in yeast S. cerivisae includepYepSecl(Baldari, et al., (1987) EMBO J. 6:229-234), pMFa (Kurjan andHerskowitz, (1982) Cell 30:933-943), pJRY88 (Schultz et al., (1987) Gene54:113-123), pYES2 (Invitrogen Corp. San Diego, Calif.), and picZ(Invitrogen Corp. San Diego, Calif.).

Alternatively, the polypeptides can be expressed in insect cells usingbaculovirus expression vectors. Baculovirus vectors available forexpression of proteins in cultured insect cells (e.g., Sf9 cells)include the pAc series (Smith et al. (1983) Mol. Cell Biol. 3:2156-2165)and the pVL series (Lucklow and Summers (1989) Virology 170:31-39).

In yet another embodiment, a nucleic acid of the invention is expressedin mammalian cells using a mammalian expression vector. Examples ofmammalian expression vectors include pCDM8 (Seed, B. (1987) Nature329:840) and pMT2PC (Kaufman et al. (1987) EMBO J. 6:187-195). When usedin mammalian cells, the expression vector's control functions are oftenprovided by viral regulatory elements. For example, commonly usedpromoters are derived from polyoma, Adenovirus 2, cytomegalovirus andSimian Virus 40. For other suitable expression systems for bothprokaryotic and eukaryotic cells see chapters 16 and 17 of Sambrook, J.,Fritsh, E. F., and Maniatis, T, Molecular Cloning: A Laboratory Manual.2^(nd), ed., Cold Spring Harbor Laboratory, Cold Spring HarborLaboratory Press, Cold Spring Harbor, N.Y., 1989.

In another embodiment, the recombinant mammalian expression vector iscapable of directing expression of the nucleic acid preferentially in aparticular cell type (e.g., tissue-specific regulatory elements are usedto express the nucleic acid). Tissue-specific regulatory elements areknown in art. Non-limiting examples of suitable tissue-specificpromoters include the albumin promoter (live-specific; Pinkert et al.(1987) Genes Dev. 1:268-277), lymphoid-specific promoters (Calame andEaton (1988) Adv. Immunol. 43:235-275), in particular promoters ofT-cell receptors (Winoto and Baltimore (1989) EMBO J. 8:729-733) andimmunoglobulins (Banerji et al. (1983) Cell 33:729-740; Queen andBaltimore (1983) Cell 33:741-748), neuron-specific promoters (e.g., theneurofilament promoter, Byrne and Ruddle (1989) Proc. Natl. Acad. Sci.USA 86:5473-5477), pancreas-specific promoters (e.g., milk wheypromoter; U.S. Pat. No. 4,873,316 and European Application PublicationNo. 264,166). Developmentally-regulated promoters are also encompassed,for example the murine box promoters (Kessek and Gruss (1990) Science249:374-379) and the α-fetoprotein promoter (Campes and Tilghman (1989)Genes Dev. 3:537-546). 100761 Another aspect of the invention pertainsto host cells into which a nucleic acid molecule encoding a polypeptideof the invention is introduced within a recombinant expression vector ora nucleic acid molecule containing sequences which allow it tohomologously recombine into a specific site of the host cell's genome.The terms “host cell” and “recombinant host cell” are usedinterchangeably herein. It is understood that such terms refer not onlyto the particular subject cell but to the progeny or potential progenyof such a cell. Because certain modifications may occur in succeedinggenerations due to either mutation or environmental influences, suchprogeny may not, in fact, be identical to the parent cell, but are stillincluded within the scope of the term as used herein.

A host cell can be any prokaryotic or eukaryotic cell. For example, apolypeptide of the invention can be expressed in bacterial cells such asE. coli, insect cells, yeast or mammalian cells (such as Chinese hamsterovary cells (CHO) or COS cells). Other suitable host cells are known tothose skilled in the art.

Vector DNA can be introduced into prokaryotic or eukaryotic cells viaconventional transformation or transfection techniques. As used herein,the terms “transformation” and “transfection” are intended to refer to avariety of art-recognized techniques for introducing foreign nucleicacid (e.g., DNA) into a host cell, including calcium phosphate orcalcium chloride co-precipitation, DEAE-dextran-mediated transfection,lipofection, or eletroporation. Suitable methods for transforming ortransfecting host cells can be found in Sambrook, et al. (MolecularCloning: A Laboratory Manual. 2^(nd), ed., Cold Spring HarborLaboratory, Cold Spring Harbor Laboratory Press, Cold Spring Harbor,N.Y., 1989), and other laboratory manuals.

For stable transfection of mammalian cells, it is known that, dependingupon the expression vector and transfection technique used, only a smallfraction of cells may integrate the foreign DNA into their genome. Inorder to identify and select these integrants, a gene that encodes aselectable marker (e.g., resistance to antibiotics) is generallyintroduced into the host cells along with the gene of interest.Preferred selectable markers include those which confer resistance todrugs, such as G418, hygromycin and methotrexate. A nucleic acidencoding the polypeptide of the invention can be introduced on aseparate vector. Cells stably transfected with the introduced nucleicacid can be identified by drug selection (e.g., cells that haveincorporated the selectable marker gene will survive, while the othercells die).

A host cell of the invention, such as a prokaryotic or eukaryotic hostcell in culture, can be used to produce (i.e., express) the polypeptidesof the invention. Accordingly, the invention further provides methodsfor producing polypeptides using the host cells of the invention. In oneembodiment, the method comprises culturing the host cell of theinvention (into which a recombinant expression vector encoding apolypeptide of the invention has been introduced) in a suitable mediumsuch that a polypeptide of the invention is produced. In anotherembodiment, the method further comprises isolating the polypeptide fromthe medium or the host cell.

The host cells of the invention can also be used to produce non-humantransgenic animals. For example, in one embodiment, a host cell of theinvention is a fertilized oocyte or an embryonic stem cell into whichcoding sequences have been introduced. Such host cells can then be usedto create non-human transgenic animals in which exogenous sequences havebeen introduced into their genome or homologous recombinant animals inwhich endogenous sequences have been altered. As used herein, a“transgenic animal” is a non-human animal, preferably a mammal, morepreferably a rodent such as rat or mouse, in which one or more of thecells of the animal includes transgene. Other examples of transgenicanimals include non-human primates sheep, dogs, cows, goats, chickens,amphibians, and the like. A transgene is exogenous DNA which isintegrated into the genome of a cell from which a transgenic animaldevelops and which remains in the genome of the mature animal, therebydirecting the expression of an encoded gene product in one or more celltypes or tissues of the transgenic animal. As used herein, a “homologousrecombinant animal” is a non-human animal, preferably a mammal, in whichan endogenous gene has been altered by homologous recombination betweenthe endogenous gene and an exogenous DNA molecule introduced into a cellof the animal, e.g., an embryonic cell of the animal, prior todevelopment of the animal.

A transgenic animal of the invention can be created by introducing anucleic acid into the male pronuclei of a fertilized oocyte, e.g., bymicroinjection, retroviral infection, and allowing the oocyte to developin a pseudopregnant female foster animal. The cDNA sequence encoding apolypeptide of the invention can be introduced as a transgene into thegenome of a non-human animal. Intronic sequences and polyadenylationsignals can also be included in the transgene to increase the efficiencyof expression of the transgene. A tissue-specific regulatory sequence(s)can be operably linked to a transgene to direct expression of a proteinto particular cells. Methods for generating transgenic animals viaembryo manipulation and microinjection, particularly animals such asmice, have become conventional in the art and are described, forexample, U.S. Pat. No. 4,873,191 by Wagner et al. and in Hogan, B.,Manipulating the Mouse Embryo, (Cold Spring Harbor Laboratory Press,Cold Spring Harbor, N.Y., 1986). Similar methods are used for productionof other transgenic animals. A transgenic founder animal can beidentified based upon the presence of a transgene in its genome and/orexpression of mRNA in tissues or cells of the animals. A transgenicfounder animal can then be used to breed additional animals carrying thetransgene. Moreover, transgenic animals carrying a transgene encoding aprotein can further be bred to other transgenic animals carrying othertransgenes.

In another embodiment, transgenic non-humans animals can be producedwhich contain selected systems which allow for regulated expression ofthe transgene. One example of such a system is the cre/loxP recombinasesystem of bacteriophage P1. For a description of the cre/loxPrecombinase system, see, e.g., Lakso et al. (1992) Proc. Natl. Acad.Sci. USA 89:6232-6236. Another example of a recombinase system is theFLP recombinase system of Saccharomyces cerevisiae (O'Gorman et al.(1991) Science 251:1351-1355. If a cre/loxP recombinase system is usedto regulate expression of the transgene, animals containing transgenesencoding both the cre recombinase and a selected protein are required.Such animals can be provided through the construction of “double”transgenic animals, e.g., by mating two transgenic animals, onecontaining a transgene encoding a selected protein and the othercontaining a transgene encoding a recombinase.

Clones of the non-human transgenic animals described herein can also beproduced according to the methods described in Wilmut, I. et al. (1997)Nature 385:810-813 and PCT International Publication Nos. WO97/07668 andWO97/07669. In brief, a cell, e.g., a somatic cell, from the transgenicanimal can be isolated and induced to exit the growth cycle and enter Gophase. The quiescent cell can then be fused, e.g., through the use ofelectrical pulses, to enucleated oocyte from an animal of the samespecies from which the quiescent cell is isolated. The reconstructedoocyte is then cultured such that it develops to morula or blastocyteand then transferred to pseudopregnant female foster animal. Theoffspring borne of this female foster animal will be a clone of theanimal from which the cell, e.g., the somatic cell, is isolated.

Methods of Making the Molecules of the Invention

As described above, molecules of the invention may be made recombinantlyusing the nucleic acid molecules, vectors, and host cells describedabove.

Alternatively, the targeting moiety can be made synthetically, orisolated from a natural source and linked to the channel-forming moietyusing methods and techniques well known to one of the skill in the art.

Further, to increase the stability or half life of the compounds of theinvention, the peptides may be made, e.g., synthetically orrecombinantly, to include one or more peptide analogs or mimetics.Exemplary peptides can be synthesized to include D-isomers of thenaturally occurring amino acid residues to increase the half life of themolecule when administered to a subject.

Pharmaceutical Compositions

The molecule of the invention (also referred to herein as “activecompounds”) of the invention can be incorporated into pharmaceuticalcompositions suitable for administration. Such compositions typicallycomprise the active compound and a pharmaceutically acceptable carrier.As used herein the language “pharmaceutically acceptable carrier” isintended to include any and all solvents, dispersion media, coatings,antibacterial and anitfungal agents, isotonic and absorption delayingagents, and the like, compatible with pharmaceutical administration. Theuse of such media and agents for pharmaceutically active substances iswell known in the art. Except in so far as any conventional media oragent is incompatible with the active compound, use thereof in thecompositions is contemplated. Supplementary active compounds can also beincorporated into the compositions.

A pharmaceutical composition of the invention is formulated to becompatible with its intended route of administration. Examples of routesof administration include parenteral, e.g., intravenous, intradermal,subcutaneous, oral (e.g., inhalation), transdermal (topical),transmucosal, and rectal administration. Solutions or suspensions usedfor parenteral, intradermal, or subcutaneous application can include thefollowing components: a sterile diluent such as water for injection,saline solution, fixed oils, polyethylene glycols, glycerine, propyleneglycol or other synthetic solvents; antibacterial agents such as benzylalcohol or methyl parabens; antioxidants such as ascorbic acid or sodiumbisulfite; chelating agents such as ethylenediaminetetraacetic acid;buffers such as acetates, citrates or phosphates and agents for theadjustment of tonicity such as sodium chloride or dextrose. PH can beadjusted with acids or bases, such as hydrochloric acid or sodiumhydroxide. The parenteral preparation can be enclosed in ampoules,disposable syringes or multiple dose vials made of glass or plastic.

Pharmaceutical compositions suitable for injectable use include sterileaqueous solutions (where water soluble) or dispersions and sterilepowders for the extemporaneous preparation of sterile injectablesolutions or dispersion. For intravenous administration, suitablecarriers include physiological saline, bacteriostatic water, CremophorEL™ (BASF, Parsippany, N.J.) or phosphate buffered salines (PBS). In allcases, the composition must be sterile and should be fluid to the extentthat easy syringability exists. It must be stable under the conditionsof manufacture and storage and must be preserved against thecontaminating action of microorganism such as bacteria and fungi. Thecarrier can be a solvent or dispersion medium containing, for example,water, ethanol, polyol (for example, glycerol, propylene glycol, andliquid polyethylene glycol, and the like), and suitable mixturesthereof. The proper fluidity can be maintained, for example, by the useof a coating such as lecithin, by the maintenance of the requiredparticle size in the case of dispersion and by the use of surfactants.Prevention of the action of microorganisms can be achieved by variousantibacterial and antifungal agents, for example, parabens,chlorobutanol, phenol, ascorbic acid, thimerosal, and the like. In manycases, it will be preferable to include isotonic agents, for example,sugars, polyalcohols such as manitol, sorbitol, sodium chloride in thecomposition. Prolonged absorption of the injectable compositions can bebrought about by including in the composition an agent which delaysabsorption, for example, aluminum monostearate and gelatin.

Sterile injectable solutions can be prepared by incorporating the activecompound in the required amount in an appropriate solvent with one or acombination of ingredients enumerated above, as required, followed byfiltered sterilization. Generally, dispersions are prepared byincorporating the active compound into a sterile vehicle which containsa basic dispersion medium and the required other ingredients from thoseenumerated above. In the case of sterile powders for the preparation ofsterile injectable solutions, the preferred methods of preparation arevacuum drying and freeze-drying which yields a powder of the activeingredients plus any additional desired ingredient from a previouslysterile-filtered solution thereof.

Oral compositions generally include an inert diluent or an ediblecarrier. They can be enclosed in gelatin capsules or compressed intotablets. For the purpose of oral therapeutic administration, the activecompound can be incorporated with excipients and used in the form oftablets, troches or capsules. Oral compositions can also be preparedusing a fluid carrier for use as a mouthwash, wherein the compound inthe fluid carrier is applied orally and swished and expectorated orswallowed. Pharmaceutically compatible binding agents, and/or adjuvantmaterials can be included as part of the composition. The tablets,pills, capsules, troches and the like can contain any of followingingredients, or compounds of a similar nature: a binder such asmicrocrystalline cellulose, gum tragacanth or gelatin; an excipient suchas starch or lactose, a disintegrating agent such as alginic acid,Primogel, or corn starch, a lubricant such as magnesium stearate orSterotes; a glidant such as colloidal silicon dioxide; a sweeteningagent such as sucrose or saccharin; or flavoring agent such aspeppermint, methyl salicylate, or orange flavoring.

For administration by inhalation, the compounds are delivered in theform of an aerosol spray from pressured container or dispenser whichcontains a suitable propellant, e.g., a gas such as carbon dioxide, or anebulizer.

Systemic administration can also be by transmucosal or transdermalmeans. For transmucosal or transdermal administration, penetrantsappropriate to the barrier to be permeated are used in the formulation.Such penetrants are generally known in the art, and include, forexample, for transmucosal administration, detergents, bile salts, andfusidic acid derivatives. Transmucosal administration can beaccomplished through the use of nasal spray or suppositories. Fortransdermal administration, the active compounds are formulated intoointments, salves, gels, or creams as generally known in the art.

The compounds can also be prepared in the form of suppositories (e.g.,with conventional suppository bases such as cocoa butter and otherglycerides) or retention enemas for rectal delivery.

In one embodiment, the active compounds are prepared with carriers thatwill protect the compound against rapid elimination from the body, suchas controlled release formulation, including implants andmicroencapsulated delivery systems. Biodegradable, biocompatiblepolymers can be used, such as ethylene vinyl acetate, polyanhydrides,polyglycolic acid, collagen, polyorthoesters, and polyacetic acid.Methods for preparation of such formulations will be apparent to thoseskilled in the art. The materials can also be obtained commercially fromAlza Corporation and Nova Pharmaceuticals, Inc. Liposomal suspensions(including liposomes targeted to infected cells with monoclonalantibodies to viral antigens) can also be used as pharmaceuticallyacceptable carriers. These can be prepared according to methods known tothose skilled in the art, for example, as described in U.S. Pat. No.4,522,811.

It is especially advantageous to formulate oral or parenteralcompositions in dosage unit form for ease of administration anduniformity of dosage. Dosage unit form as used herein refers tophysically discrete units suited as unitary dosages for the subject tobe treated; each unit containing a predetermined quantity of activecompound calculated to produce the desired therapeutic effect inassociation with the required pharmaceutical carrier. The specificationfor the dosage unit forms of the invention are dictated by and directlydependent on the unique characteristics of the active compound and theparticular therapeutic effect to be achieved, and the limitationsinherent in the art of compounding such an active compound for thetreatment of individuals.

Toxicity and therapeutic efficacy of such compounds can be determined bystandard pharmaceutical procedures in cell cultures or experimentalanimals, e.g., for determining the LD50 (the dose lethal to 50% of thepopulation) and the ED50 (the dose therapeutically effective in 50% ofthe population). The dose ration between toxic and therapeutic effectsis the therapeutic index and it can be expressed as the ratio LD50/ED50.Compounds which exhibit large therapeutic indices are preferred. Whilecompounds that exhibit toxic side effects may be used, care should betaken to design a delivery system that targets such compounds to thesite of affected tissue in order to minimize potential damage touninfected cells and, thereby, reduce side effects.

The data obtained from the cell culture assays and animal studies can beused in formulating a range of dosage for use in humans. The dosage ofsuch compounds lies preferably within a range of circulatingconcentrations that include the ED50 with little or no toxicity. Thedosage may vary within this range depending upon the dosage formemployed and the route of administration utilized. For any compound usedin the method of the invention, the therapeutically effective dose canbe estimated initially form cell culture assays. A dose may beformulated in animal models to achieve a circulating plasmaconcentration range that includes the IC50 (i.e., the concentration ofthe test compound which achieves a half-maximal inhibition of symptoms)as determined in cell culture. Such information can be used to moreaccurately determine useful doses in humans. Levels in plasma may bemeasured, for example, by high performance liquid chromatography.

The pharmaceutical compositions can be included in a container, pack, ordispenser together with instructions for administration.

Methods of Treatment

The present invention provides therapeutic methods of treating a subjecthaving a cell proliferative disorder. In certain embodiments, the cellproliferative disorder is cancer. In a specific embodiment, the cellproliferative disorder is a viral associated cancer.

As used herein, the term “treating” refers to the administration of atherapeutically effective amount of an active compound to a subject, forprophylactic and/or therapeutic purposes. The term “administration”includes delivery to a subject, e.g., by any appropriate method whichserves to deliver the drug to the site of the cancer. Administration ofthe drug can be, e.g., oral, intravenous, or topical (as described infurther detail below).

In a one embodiment, a subject having a cell proliferative disorder istreated with an effective amount of an active compound of the inventionsuch that the cell proliferative disorder is treated. In a specificembodiment, the subject that is being treated has cancer.

In one embodiment, a composition of the invention is administered to asubject in combination with additional agents, e.g., other compositionsuseful for treating cell proliferative disorders.

The composition of the invention can be administered to a subject inneed of treatment in an effective amount using the pharmaceuticalcompositions described herein.

This invention is further illustrated by the following examples whichshould not be construed as limiting. The contents of all references,patents and published patent applications cited throughout thisapplication are incorporated herein by reference.

EXEMPLIFICATION Example 1 Cytocidal Effects on Burkitt Lymphoma Cells

A fusion peptide that has been identified as pheromonicin-EBV (Ph-EBV)was created incorporating a peptide chain of colicin Ia with areconstituted mimetic of V_(H)CDR1IV_(L)CDR3 pair of ATCC HB-168monoclonal IgG fragment, two CDR linked to the HB-168 IgGV_(H)CDR1/V_(H)CDR2 linker, SFGMHWVRQAPEKGLEWVAGQGY SYPYT (SEQ ID NO:5)having the nucleic acid sequence of SEQ 1D NO:6, and was introducedfollowing C-terminus of colicin Ia (1626) to form a 654 residue peptide(SEQ ID NO:7) having the nucleic acid sequence of SEQ ID NO:8.

A second fusion peptide that has been denominated as pheromonicin-CNCV(Ph-CNCV), was created by incorporating a peptide chain of colicin Iawith a phage segment of filamentous bacteriophage M13, TLTTKLY (SEQ IDNO:9) having the nucleic acid sequence of SEQ ID NO:10, and wasintroduced following the C-terminus of colicin Ia (1626) to form a 633residue peptide (SEQ ED NO:11) having the polynucleotide sequence of SEQID NO:12.

Ph-EBV and Ph-CNCV both demonstrated cytocidal effects on EBV-infectedtumor cells (Ragi cell) in vitro (FIGS. 3, 4 and 6, respectively). Incontrast, neither peptide demonstrated cytocidal effects on normalmammalian cells and malignant cells with no virus gene transferred(FIGS. 5, 7, 8, and 9, respectively).

Human Burkitt malignant lymphoma cell strain ATCC CCL-86 (Epstein-Barrvirus positive) and human acquired immunodeficiency syndrome (AIDS)related body cavity based lymphoma cell strain ATCC CRL-2230(Epstein-Barr virus and Kaposi sarcoma associated herpesvirus positive)were used to test in vitro cell growth inhibition. Assays were performedin Falcon 3046 six-well tissue culture plate containing 3 ml of PRMI1640 medium, at 37° C. and monitored with a Olympus IX-71 invertedmicroscope/colored CCD every 24 hours. After approximately 12 hours thecell density reached about 10⁵ cell/ml. Test agents were added once celldensities reached 10⁵ cell/ml. Cell death was monitored and 50 nMacridinorange/600 nM propidium iodide fluorescent dyes were added 72hours after the test agents were added.

Ph-EBV and Ph-CNCV were added to human Burkitt malignant lymphoma cellcultures at concentration of 50 μg/ml (FIGS. 3B and 4B). An equivalentamount of PBS stock solution (pH7.4, 10 mM PBS, 0.2M NaCl)(FIGS. 3A and4A) as controls. 50 μg/ml Ph-EBV killed about 60-70% and 50 μg/mlPh-CNCV killed about 30-40% of the lymphoma cells after 72 hours ofincubation.

To assess the potential targeting efficiency of Ph-EBV and Ph-CNCV tonormal and malignant mammalian cells, ATCC CRL-1648 human Burkittmalignant lymphoma cells (Epstein-Barr virus negative) ATCC 3T3 mousefibroblast, ECV-304 human umbilical cord vein endothelium and SMMC-7721human hepatocellular cancer cells (Institute of Biochemistry& CellBiology, Shanghai, Chinese Academy of Science) were incubated withPh-Ph-EBV and Ph-CNCV 200 μg/ml respectively over 96 hours. Nodifference in cell counts was observed. Further, cell morphology andlactate dehydrogenase levels in cultured cells were consistent whencompared to untreated controls. The data indicate that two anticancerpeptides present good targeting efficiency to malignant cells with virusantigen presented on their cell membranes.

Example 2 In Vivo Elimination Effects against EBV-Associated Human TumorXenografts in Immunodeficiency Mice

To assess the effects of pheromonicin in vivo, solid tumor models wereset up in two species of immunodeficiency mice by inoculation eitherEBV-infected or uninfected human tumor cells to identify whetherpheromonicin inhibited the proliferation of solid tumors.

In SCID Beige mice, neoplasms were inoculated either with EBV-infectedATCC CCL-86 (left side) or with EBV-uninfected ATCC CRL-1648 (rightside) Burkitt Lymphoma cells respectively at forelimb armpits of thesame mouse and grew up to 1×1×1 mm in 7 days. The 20-d treatment wasstarted eight days after the tumor cell inoculation. Pheromonicin wasinjected intraperitoneally each day (0.28 μM/gram bodyweight/day). Atthe end of treatment, the right neoplasms of treated mice (n=10) grew upto 8×6×2 mm or larger as well as both neoplasms of controls (n=10,intraperitoneal spared stock solution 0.5 ml/day) (FIGS. 10A and B).Whereas the left neoplasm sizes of treated mice were 3×2×2 mm or smaller(FIG. 10B). Neoplasms were isolated carefully and weighted forquantitative analysis. Microscopic examination demonstrated that massproliferation existed in all CRL-1648 neoplasms of treated mice,CRL-1648 and CCL-86 neoplasms of controls (FIG. 10C-E). Whereas eithercoagulative necrosis spread to the entire cell population or onlynecrotic entities remained in the CCL-86 neoplasms of treated mice (FIG.10F).

In BALB/C nude mice, only EBV-infected ATCC CCL-86 inoculated at rightforelimb armpit area. The 20-d intraperitoneal pheromonicin treatmentstarted at the 8^(th) day of inoculation while the neoplasms grew up to1×1×1 mm in all mice. At the end of the 20-d experimental period,neoplasm of control mice (n=10, intraperitoneal spared stock solution0.5 ml/day) grew up to 8×6×3 mm or larger (FIG. 11A). Whereas theneoplasms of treated mice (n=10, intraperitoneal pheromonicin 0.27nM/gram bodyweight/day) either disappeared or shrank to smaller than1×1×1 mm sizes with bodyweight gaining. Autopsy found that eitherneoplasm were smaller than 1×1×1 mm in 7 of them or no visible neoplasmdetected in the rest three (FIG. 11C). Microscopic examinationdemonstrated that only necrotic entities remained in either visible ormicroscopic neoplasm with pheromonicin treatment (FIG. 11D). Three invivo assays were done for control and pheromonicin treatmentrespectively.

To determine whether that elimination activity of pheromonicin wasuniversal to other EBV-infected tumors, AIDS related body cavity basedlymphoma (ATCC CRL-2230 strain, EBV+)(AIDSL) and nasopharyngeal cancer(TNE-1 strain, EBV+, Institute of Cancer Research, Hunan University ofMedical Sciences, Changsha, Hunan, China)(NC) cells were inoculated intoBALB/C nude mice respectively and mice were treated as to what performedin the BL experiment. FIG. 11 G-H shows that pheromonicin presentedidentical elimination effects in the AIDSL neoplasm. The NC neoplasm,however, was not eliminated so keen as to what occurred in the BL andAIDSL cases. At the end of 20-d treatment, encapsulated NC cells wereundergoing coagulative necrosis in the shrunk NC neoplasm (Inset of FIG.11L).

Taken together, there were 30 treated cases and 30 control cases in eachBL, AIDSL and NC experiments. Total weight of all visible neoplasms incontrol or treated experiments (no visible neoplasm were counted aszero) was added up for quantitative analysis. There were statisticallysignificance differences in total weight of neoplasms between controland treated BL neoplasm (p<0.0.001), AIDSL neoplasm (p<0.0.001) and NCneoplasm (p<0.0.001).

Example 3 In vivo Penetration Effects into Solid Tumor Model inImmunodeficiency Mice

In vivo distribution of circulating pheromonicin molecules were observedwith fluorescent-labeling imagine system in the animals with aninoculated xenograft. One hour after intraperitoneal injection, theFITC-labeled pheromonicin molecules started to accumulate inside theimplanted solid tumor of EBV-induced cells. The accumulation lastedapproximately 6 hours. At least half of the systemic distributedpheromonicin had been cleared by approximately 4 hours after injectionthrough urination (Figures A-D). Conversely, there was no accumulationin the implanted solid tumor of EBV-uninfected cells. In addition, therewas no accumulation of the FITC-labeled HB-168 monoclonal IgG againstEBV gp350/220 envelope antigen, the template of mimetic targetingsegment of Ph-EBV, in either EBV-induced tumor or EBV-uninfected tumor.There was some accumulation encircling the boundaries of the EBV-inducedtumor (Figure E-F). PMC-SA, a control pheromonicin againstStaphylococcus aureus fused to a staphylococcal pheromone to colicin Ia,did not present any specific accumulation in both tumors but presentedidentical systemic distribution and clearance of pheromonicin-EBVmolecules (Figure G). These results indicate that at least in testedmice, pheromonicin was cleared rapidly and had much better penetrationand accumulation abilities than that of intact IgG molecules againsttargeted solid tumors.

Example 4 Assessment of Toxicity of Pheromonicin to Mammalian Cells

There was no microscopic evidence of necrosis or inflammation in thelivers, intestines, kidneys or spleens of the regular mice received30-day intraperitoneal pheromonicin treatment (700μg/mouse/day)(n=10)(FIG. 13A-D). These data suggest that pheromonicinmay be tolerated by mammalian systems without evident toxicity.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

What is claimed is:
 1. A method of treating a subject having a cellproliferative disorder, the method comprising: administering to saidsubject an effective amount of a polypeptide comprising a targetingagent and a channel-forming moiety, thereby treating said subject. 2.The method of claim 1, wherein said targeting agent is selected from anantibody, an antibody fragment, and a reconstructed antibody mimetic. 3.The method of claim 2, wherein said targeting agent is specific for apolypeptide that is differentially expressed in cancer cells.
 4. Themethod of claim 1, wherein said channel-forming moiety is selected fromthe group consisting of alpha-hemolysin, delta toxin, diphtheria toxin,anthrax toxin, and E1 family colicin, or a channel-forming domainthereof.
 5. The method of claim 4, wherein said channel-forming domainof colicin is selected from the group consisting of colicin E1, Ia, Ib,A, K or N.
 6. The method of claim 5, wherein said colicin is colicin Ia.7. The method of claim 6, wherein said channel-forming fragmentcomprises 451-626 amino acid residues of colicin Ia (Seq ID No.1). 8.The method of claim 1, wherein said cell proliferative disorder iscancer.
 9. The method of claim 8, wherein said cancer is a viralassociated cancer.
 10. The method of claim 8, wherein said cancer isselected from the group consisting of a cancer formed in the larynx, theprostate, the stomach, the skin, the oral cavity, the pharynx, theesophagus, the liver, the lung, the head, the neck, the bronchus, thepancreas, the small intestine, the colon, the rectum, the breast, thebladder, the uterus, the brain, the lymph system, the blood, theovaries, the kidneys, and soft tissue.
 11. A method of treating asubject having a cell proliferative disorder, the method comprising:administering to said subject an effective amount of a polypeptidecomprising reconstructed antibody mimetic derived from engineeredantibody variants against Epstein-Barr virus gp350/220 and achannel-forming domain of colicin, thereby treating said subject. 12.The method of claim 11, wherein said reconstructed antibody mimeticcomprises two CDRs of the antibody and a polypeptide linker, wherein thetwo CDRs are covalently linked by the polypeptide linker, wherein saidantibody specifically binds Epstein-Barr virus gp350/220.
 13. The methodof claim 12, wherein one of the CDR is CDR1 of a heavy chain variabledomain and the other CDR is CDR3 of a light chain variable domain. 14.The method of claim 13, the amino acid sequence of the reconstructedantibody mimetic is Seq ID No.5.
 15. The method of claim 12, whereinsaid polypeptide consisting essentially of the amino acid sequence ofSEQ ID NO:
 7. 16. The method of any of claims 1, further comprisingproviding a nucleic acid molecule encoding the polypeptide.
 17. Themethod of 16, further comprising transfecting a host cell with thenucleic acid molecule.
 18. The method of 17, wherein said nucleic acidmolecule has the nucleic acid sequence of SEQ ID NO: 8.